Did f4u4's R2800-18W run at 70'' and with 2800HP at sealevel?

[adamliu]

I found that NACA report "Measurements in Flight of the Flying Qualities of a Chance Vought F4U-4 Airplane: TED No. NACA 2388"
stated that it could run 2800HP at sealevel.
https://ww2aircraft.net/forum/attachments/f4u-4_r280018w_naca-jpg.576808/
however on other sources, F4U4 with R2800-18W was only to be 2450HP wep.

Was F4u4's R2800-18W ever set up to be 2800HP?

 

[Dawncaster]

F4U-4's maximum performances

 

[adamliu]

F4U-4's maximum performances

Hey

this one shows that at sea level f4u4with r2800-18w can only get to 2650hp

 

[Metrallaroja]

I found that NACA report "Measurements in Flight of the Flying Qualities of a Chance Vought F4U-4 Airplane: TED No. NACA 2388"
stated that it could run 2800HP at sealevel.
https://ww2aircraft.net/forum/attachments/f4u-4_r280018w_naca-jpg.576808/
however on other sources, F4U4 with R2800-18W was only to be 2450HP wep.

Was F4u4's R2800-18W ever set up to be 2800HP?

Hi, A adamliu

This isn't for F4U-4 but for F4U-7 using 115/145 from 1954 F4U-7 flight handbook AN 01-45HDB-1:
It doesnt match with rated brake horsepower of 1944 in supercharger critical alts as you can see.
At Neutral it could be that it developed 2650hp without ram and that is why it is noted as F.T. and 2800HP at 70'' with ram. F.T is sometimes also used for crit alt, so maybe it could achieve 70'' and 2800Hp without ram air.
I dont know if anyone would have an idea or a source of how it would be the power graph for this settings of -18w in F4U-7.

In military power we know that:
2500 feet (crit alt) --> 2300HP 59,5'' (Neutral)
18000 feet (crit alt) --> 1900HP 54.5'' (Low)
25000 feet (crit alt) --> 1720HP 54.5'' (High)

 

[BiffF15]

Hi, A adamliu

This isn't for F4U-4 but for F4U-7 using 115/145 from 1954 F4U-7 flight handbook AN 01-45HDB-1:
It doesnt match with rated brake horsepower of 1944 in supercharger critical alts as you can see.
At Neutral it could be that it developed 2650hp without ram and that is why it is noted as F.T. and 2800HP at 70'' with ram. F.T is sometimes also used for crit alt, so maybe it could achieve 70'' and 2800Hp without ram air.
I dont know if anyone would have an idea or a source of how it would be the power graph for this settings of -18w in F4U-7.

In military power we know that:
2500 feet (crit alt) --> 2300HP 59,5'' (Neutral)
18000 feet (crit alt) --> 1900HP 54.5'' (Low)
25000 feet (crit alt) --> 1720HP 54.5'' (High)

View attachment 646444

Fuel flow at 5k on the combat rated chart seems incorrect. Anyone have a reason its not a typo?

 

[Geoffrey Sinclair]

USN F4U-4 Airplane Characteristics and Performance as of 1 March 1946, P&W R-2800-18W, BHP/RPM/Altitude (feet) or BHP/Altitude (feet)
Combat power 2380/2800/0, 2170-2260/2900-17000, 2050-2080/19500-23300
Military power 2100/2800/0-4300, 1810-1885/8600-18000, 1690-1710/20700-25000
Normal 1700/2600/0-9000, 1630/10200-20000, 1550/21300-26600
Take off 2100 BHP, 2800 RPM

 

[GregP]

You need to keep in mind that once the war was over, the use of WER (War Emergency Rating) power was severely restricted. WER was there to save the life of a pilot who otherwise might be killed. After the war was over, there was no real reason to allow WER use, and it was severely restricted. In some units, it was a major writeup to break the throttle wire barrier to use WER.

I know 8+ former jet fighter pilots who all flew Mach 2+ airplanes, but they all say they almost never got to Mach 2 except for once or twice in their careers.

Post-war, they DID need to train realistically, but they didn't need to use WER to do it, at least not often. It is one thing to set a time-to-climb record with an F8F Bearcat. It is quite another to let all the Air National Guard pilots try that every month on their flight weekend.

As any good hot-rodder knows, "Speed costs. How fast is your wallet?" Post-war F4U-4 performance was likely more reduced by Squadron / Wing regulations and budget constraints than any lack of ability to produce the power. They DID reach a point where all a squadron or wing leader had to do to lose his job was to have a flying accident. Upper-end performance includes greatly-increased risks of accidents. They lost an F-14 Tomcat on a cruise home once during a Mach 1 flyby.

 

[Metrallaroja]

What does this have to do with F4U-4 or F4U-7? This planes did saw war operations with 115/145 in korea/indochina.
Also water injection isn't even close to how dangerous are +1 match operations. It even saves fuel compared to Military Ratings in R-2800.

 

[SaparotRob]

It's why some post war stats are lower.

 

[Metrallaroja]

F7F, F8F, F4U-4, F4U-5, AU-1, F4U-7 they all got 115/145 after the war and were officially released to 2300HP at Military Ratings instead of 2100HP.
If AU-1 achieved 2800HP why wouldnt the rest corsairs.

 

[GregP]

Yes they were released to those levels, but not for frequent use. Operational restrictions were very REAL. The government didn't want to PAY for the increased maintenance required by using extreme performance power settings during peacetime on a regular basis. If you don't understand that, you haven't absorbed actual non-war flight operational restrictions of piston military aircraft.

That's not wrong in any way, but asking "what does that have to do with it?" might indicate some need to look at peacetime flight operational safety realities before saying they weren't real. We were losing 170 planes a day during WWII, counting ferry operations, combat, operational, training and CONUS flights. That was just unacceptable to everyone after hostilities had ceased.

We have some former Air Force and Navy pilots in here as members. I wonder what THEY have to say about aircraft performance during peacetime operations?

 

[Metrallaroja]

I wonder what THEY have to say about aircraft performance during peacetime operations?

Korea and Indochina are peacetime operations?

 

[BiffF15]

Korea and Indochina are peacetime operations?

Metrallaroja,

Korea and Indochina were both combat operations. However, it's my opinion that the threat level was very different than in WW2. As was the allowance of how hard you could push your plane. We're the Allies launching AAF / USAF planes off carriers, losing entire squadrons to weather during escort or movement operations, or a pilot crashing a plane one day and flying the next? The reason was the attitude and approach to flying had matured, and the risks were more measured and not taken without a higher chance of return on your investment.

As Greg said above, the power was still available, but the reasons to use it, and the frequency of it occurring had grown much more restrictive. Remember, after each large growth period the military has is followed by a contraction. During the contractions, and the gradual growth out of it, money is very tight, as is personel to work on, launch, recover and fly them. The rules in general tighten down.

A classic example is alcohol in a combat theater. WW2 they drank all night long and flew the next morning. Preddy got six in one sortie while terribly hungover. Legend goes they retook the shot of him holding up 6 fingers due to his post flight / fight condition. They had alcohol in Korea and Vietnam, and maybe in Turkey during Desert Storm, but none in Saudi, Iraq, or Afghanistan since.

Flying, and the approach to it matured over time, and restrictions were usually written in bent metal and blood.

Cheers,
Biff

 

[GregP]

By the way, as you might surmise from his forum name, BiffF15 flew F-15 Eagles ... for the U.S.A..

Wish he could have taken me for a ride!

In any case, a clean F4U-4 Corsair was plenty fast and climbed quite well at WER. Less spectacular at normal power, but the potential to kill the enemy was definitely there if needed. Sea Level was really not their best-performance level, though. I've seen a pretty darn stock P-40E (John Paul's P-40) outrun a pretty darn stock F4U-4 Corsair at Reno in Bronze. That might just be the Corsair owner not pushing his engine, but they were neck and neck for 4 laps and the distance never changed more than a few feet. Of course, that's Reno, not combat ...

Cheers.

 

[Shortround6]

I would note that the AU-1 used a different supercharger than the other Corsairs.
It was a single stage, two speed unit and was more than likely related to the supercharger used on the F8F Bearcats.
In low gear near sea level it may have been able to provide the needed boost without taking as much power to drive as the two stage superchargers used in the other Corsairs. Please note the speed charts for the AU-1, the engine supercharger may have only been able to provide high boost at about 2,000ft and under in low gear.

F8F Bearcats used two different engines (actually more but some models were nearly identical) with the F8F-1s using a single stage two speed engine and the F8F-2s using a single stage, variable speed supercharger.

 

[Neil Stirling]

I found that NACA report "Measurements in Flight of the Flying Qualities of a Chance Vought F4U-4 Airplane: TED No. NACA 2388"
stated that it could run 2800HP at sealevel.
https://ww2aircraft.net/forum/attachments/f4u-4_r280018w_naca-jpg.576808/
however on other sources, F4U4 with R2800-18W was only to be 2450HP wep.

Was F4u4's R2800-18W ever set up to be 2800HP?

No.
Vought originally intended that the F4U-4 was to run its -18W at 70 "hg with 115/145 octane fuel, however, the -18W was limited to 60"hg with either 100/130 or 115/145 octane. During late 1946 the -42W was fitted to around 60 F4U-4 Corsairs and this could be run at 70"hg, however, the USN did not use this rating. Information from The Pilots Handbook for Navy Model F4U-4 Airplane AN 01-45HB-1.

Click below.

F4U-4 performance with 115/145 grade fuel?

Hi guys. I have some questions about F4U-4. Please answer the question. first see this pdf file. - http://www.wwiiaircraftperformance.org/f4u/f4u-4-detail-specification.pdf 1. When this a/c tested? A person told me, this document drawn in 1947, but It does not mean it is tested in 1947. but I...

ww2aircraft.net

Neil.

 

[Metrallaroja]

I would note that the AU-1 used a different supercharger than the other Corsairs.
It was a single stage, two speed unit and was more than likely related to the supercharger used on the F8F Bearcats.
In low gear near sea level it may have been able to provide the needed boost without taking as much power to drive as the two stage superchargers used in the other Corsairs. Please note the speed charts for the AU-1, the engine supercharger may have only been able to provide high boost at about 2,000ft and under in low gear.

Yes, -83W and -34W are very very similar in specs, but also remember that F8F-1 wasnt cleared for 70'' and 2750HP until 1949 just like F4U-5 that was cleared for 70'' and 2750HP, F8F-2 to 72'' and this information of AU-1 is from 1953. Then we have F4U-7 using the same engine as the original F4U-4 being cleared for 70'' in 1952. So I think we have an standard here.
Also to be clear if F4U-7 achieved 2800Hp was probably below 2000 feet at NEUTRAL, 2650HP in LOW until 11000feet-14000feet and 2400HP in HIGH until 20000 feet.

Vought originally intended that the F4U-4 was to run its -18W at 70 "hg with 115/145 octane fuel, however, the -18W was limited to 60"hg with either 100/130 or 115/145 octane. During late 1946 the -42W was fitted to around 60 F4U-4 Corsairs and this could be run at 70"hg, however, the USN did not use this rating. Information from The Pilots Handbook for Navy Model F4U-4 Airplane AN 01-45HB-1.

Afaik -42w is just for achieving more power at Military Power using 115/145 (which is more important than combat), 115/145 or 100/130 doesnt have an impact on water injection MP at combat. (At least between 60'' and 70'')

 

[Geoffrey Sinclair]

USN production reports,

F4U-4 using R-2800-18W in 1946.
F4U-4B using R-2800-18W/42W in 1946.
F4U-4B using R-2800-18W in 1947
F4U-4P Using R-2800-42W in 1946/7
F4U-5 using R-2800-32W in 1947/8/9
XF8F-2 using R-2800-30W in 1947
F8F-1 using R-2800-34W in 1947
F8F-2 using R-2800-30W in 1948/9

End 1946, contracts for 554 R-2800-32W with production starting in June 1947, for 496 -32W with production starting in June 1947 and 400 -42W with 175 accepted in 1946, rest by end June 1947.

R-2800-30W production ended in February 1947
R-2800-32W production on the above contract ended in October 1948 other contracts saw production continuing in 1949.
R-2800-44W, contract for 48, production began in September 1948
R-2800-48, contract for 48, production began in May 1949.